Electric-arc lamp with rotary arc.



y L. MAUCLAIRE, A. GARBARINLAND G. GAUTIER.

ELECTRIC ARC LAMP WITH ROTARY ARC.

APPLICATION FILED ocr. 23, 1917.

1,390,456. Panasept. 13, 1921.

^ UNITED STATES PATENT OFFICE.

LOUIS MAUCLAIBE, ANDR GARBARINI, AND GEORGES GAUTIER, 0F PARIS, FRANCE.

ELECTRIC-ARC LAMP WITH ROTARY ARC.

Specicatidll of Letters Patent. Patented Sept. 13, 1921,

Application med October 23, 1917. Serial No. 198,170.

To all whom. z't may concern Be it known that we, Louis .MAUCLAIRL ANDRGARBARINI, and GEORGES GAUTIER, citizens of the Re ublic of France,residing in Paris, France, have invented certain new and usefulImprovements in Electric-Arc Lamps with Rotary Arcs, of which thefollowing is a speciication.

This invention relates to improvements in the construction of electricarc lamps with a rotaryl arc, used for the production of light, for theproduction of electric oscillations, and for all other purposes.

Embodiments of the invention are illustrated in the accompanyingdrawings.

In said drawings,-

Figure 1 is a view, principally diagrammatic, illustrating oneembodiment of the present inventio Figs. 2, 3, and 4 are illustrativediagrams illustrating the action of the magnetic fields upon the arc.

Fig. 5 is a view similar to Fig. 2, illustrating another embodiment ofthe invention.

Fig. 6 is a view illustrating an embodiment of the invention in a form'somewhat more developed than in Fig. 2.

Figs. 7, 8, `and 9 are cross-sectional views of electrodes provided withaspiration conduits for drawing oif combustion products in the vicinityof the arc.

The improvements in are lam s according to this invention have for t eirobject to provide a lamp in which the rotating arc is stabilized by theuse of two groups of coils or solenoids separate one from the other;further, the central carbon which is used is prevented from burning awayprematurely by the arrangement of a refractory member into which thecarbon passes, while the same member surrounds com letely the spacebetween the central electrode and the annular electrode. Thecentralcarbon employed is moreover provided with an internal passage orpassages rendering it possible to draw away the fumes produced bytheburnin of the arc.

In te lamp which forms the sub'ect of the present invention, the arc issta ilized by usn e two groups of coils situated at O1 and y (Fig. 1),that is to say-in front of and behind the are. The line of forceproduced by this combination of two grou s of coils 4has the formindicated by t e line Z in Fig. 1, In this case when the are playscorrectly between the central electrode C and the annular electrode B,that is to sayfrom a .to b, it cuts the field normally, and consequentlya single cou le is exerted on the arc causingit to turn. I the arc tendsto play rearwardly between a1 and b1 or for wardly between a2 and b2, itwill cut the line of yforce in a variable direction.

Incase the arc plays Abetween a1 and b1 (Fig. 3) it will be seen that inaddition to the couple acting on the arc and causing it to turn, therewill be a force tending to move the arc-forwardl depending upon theangle a: which the `line Z makes with res ct to the normal n. In thecase shown in ig. 3, that is .to say during perfect working, the

normal n is coincident with the line of force Z. If the arc playsbetween a? and b2 (Fig. 5) the normal n makes an an le with the line offorce L which results 1n the production, in addition to the motivecouple producing rotation of the arc, of a force tending to move the arcback to the points a and b which correspond to normal working.

The two groups of coils O1, O2 might be arranged to have, one withrespect to the other, a preponderating action in view of the fact thatthe lamp is intended to be used for purposes requiring a very greatintensity of light in a single direction, or even for industrialpurposes for which it is de sired to obtain an emission of light whichis substantially constant in all directions (see Fig. 5).

Another disadvantage which exists in lamps with rotating arcs ashitherto known, results from the fact that when the arc is caused toplay between the central electrode C and the annular electrode B, thereis a violent movement of air which supports the combustion of .thecarbon C from the part g (Fig. 5) to the part h i, this latter part inthe only one which is useful, that 1s to sayt e crater. l

Owing to this using up of the carbon, which causes the electrodel C totaper in a conical form, the section of the carbon between the points hi becomes much smaller than the sea'tion at f g which is the normalsection of the carbon.l Under these conditions the burning away of thecarbon is very rapid, as the section of .the carbon which is reallyutilized, is not the whole section of the carbon employed, but a verymuch reduced Y section dened by the crater h i, .In order to preventthis abnormal using up of the carbon, according to this invention aninsulating member A (Fig. 6) is arranged behind the annular electrode Band bearing against this electrode, the member A being formed with acentral hole for the passage of the electrodev C. This insulating memberA, which must be capable of withstanding high temperature, is coveredinternally with a layer D consisting of a mixture of rare earths and ofthoria. With this arrangement the electrode C still becomes cut away atthe end to a conical form, but to a comparatively slight extent as Fig.7 shows, the points lrs belng much nearer to the points c d.

Moreover, as the section of the carbon at the points 1' and s is verylittle different from the section at the points 0 and d, if the closureeffected by the member A is perfect, the following phenomenon takesplace: Before the arc is started the chamber E is filled with air; whenthe arc is lighted this air allows a very slight combustion of theelectrode C to take place, but after a very short time the chamber Ewill contain only gaseous oXid or carbon, which is the only body stableat this temperature. The arc as it continues to pass thus plays in anatmosphere which does not permit any unusual burning away ott theelectrode C', the part c d alone7 which constitutes the crater, being ina state of very high incandescence.

When the lamp is to operate at a very high intensity, or when theelectrode C is placed very close to the crater of the arc of opticalappliances such as lenses, mirrors, condensers and so forth, saidelectrode C always produces some objectionablevapors. When such a lampis employed with a projector for example, it is found necessary to haverecourse to devices intended to protect the mirror from the fumesproduce-d, and a glass plate is generally inserted between the arc andthe mirror.

When the lamp is to be used for the purposes indicated above, anelectrode C is employed, according to the present invention, formed witha small internal passage x (Fig. 6), while t-he end of the electrodedistant from the crater is connected to a fiexible pipe leading to anaspirator of any suitable kind.

With this arrangement, all the fumes produced by the combustion of theelectrode C are drawn into the passage formed in this electrode and arethus removed. In addition to the great advantages of' this method ofaspiration in removing vapor and dust particles, another importantadvantage is secured resulting from the fact that the vapors and fumesare very hot, so that as they pass through the interior of the carbonthey heat and dry the same; this has the effect of improvingconsiderably the regularity of the burning of the lamp. It

is well known that when carbon electrodes are moist their operation isvery defective. Various arrangements of the passages may be used fordrawing away the vapors and fumes; for example, homogeneous carbons maybe used having central longitudinal passages (Fig. 7) or in carbonshaving cores of a dil'erent composition, the passa-ge may be formed inthe interior of the core (Fig. 8) or two, three or more passages may bearranged around the circumference of the core (Fig. 9), while of coursethe c0mposition of the carbons themselves can be varied according to theuses to which they are to be put.

Claims:

1. An arc lamp of the revolving arc type comprising a central carbonelectrode and a surrounding annular electrode, and twoseparatedsolenoids whereby the rotating arc is stabilized, saidsolenoids being substantially concentric with the axis of said centralelectrode.

2. An arc lamp according to claim 1, in which the solenolds are arrangedin planes on opposite sides of the plane of the annular electrode, andone has a preponderant effect over the other.

3. An are lamp of the revolving arc type comprising a. central carbonelectrode and a. surrounding annular non-consumable electrode, having aninsulating member, said insulating member in conjunction with saidannular electrode forming a chamber inclosing the space within theannular electrode on the side on which is mounted the central electrode.

4. An arc lamp of the revolving arc type comprising a central carbonelectrode and a surrounding annular non-consumable electrode, having aninsulating member, said insulating member in conjunction with saidannular electrode forming a chamber inclos ing the space within theannular electrode on the side on which is mounted the central electrodeand a refractory layer on said insulating member.

5. An arc lamp of the revolving arc type comprising a central carbonelectrode and a surrounding 'annular non-consumable electrode, having aninsulating member, said insulating member in conjunction with saidannular electrode forming a chamber inclosing the space within theannular electrode on the side on which is, mounted the central electrodeand asp-irating means for drawing gases of combustion from said chamber.t

6. An arc lamp of .the revolving arc type comprising a central carbonelectrode and a surrounding annular non-consumable electrode havingconnected thereto a refractory body of incandescing material formingtherewith a chamber inclosing the space within the annular electrode onthe side on which is mounted the central electrode.

7. An. are lamp according to daim Il, in In Witness Where, We havehelmmt which the central electrode has a passage signed our names in thepresence of two suhthrough it, and aspirating means for drawscribingWitnesses. ing gases of combustion through such pas- LQUIS MUCLARE 5save,

D l 'ANDRE GARBARIN 8, An are lamp accordlng to 01mm 4 m which thesenil-a1 electrode has a passage GEORGES GAUTER through it, andaspiratng means `for draw- Witnesses: ing gases of Qombustion Athroughsuch pas,l CHAS. P. PRESSLY,

` 10 sage. REN BARDY.

